##每日学习day11--2022/4/15

###filter 和map类似，参数为一个函数，一个序列

def  odd(n):

    return n%2 == 1

s = filter(odd,[1,2,3,4,5])

from collections.abc import Iterable , Iterator

print(isinstance(s,Iterator))

print(list(s))

def no_empty(s):

    return s and s.strip()

print(list(filter(no_empty,['angel a ',' ','b','','c'])))

#practice 过滤非回文数

def palindrome(num):

    n,m=0,0

    s = str(num)

    while n < len(s):

        if  s[n] == s[-n-1]:

            m+=1

        n+=1

    return m == len(s)

print(list(filter(palindrome,[123,456,123321,123454321])))

print('123'[::-1]) # 间隔选择负数，代表倒叙